This invention is related to a process for attaching a pair of headrest guide tubes on a vehicle seat frame. The guide tubes provide sockets for a pair of plastic inserts for headrest height adjustment. The height of the headrest is adjusted by adjusting the position of the pegs in the inserts.
The prior art is concerned with a method for attaching the guide tubes to the seat frame without welding, and in a minimal number of steps. One such process is described in U.S. Pat. No. 6,035,516 issued Mar. 14, 2000 to Horst Udo Petersen for xe2x80x9cSecurement of Head Rest Support into Automobile Seat Framexe2x80x9d. Petersen describes a system in which the guide tube has a preformed ring or annular enlargement. The guide tube is placed in a hole in a web in the seat frame, the ring abutting the edge of the hole. The tube and seat frame are located in a die. A punch is then lowered over the tube to form a second ring on the other side of the web. When the punch is withdrawn, the web is clamped between the two rings.
Another similar process is described in U.S. Pat. No. 5,769,499 issued Jun. 23, 1998 to Eugene S. Dudash, et al. for xe2x80x9cMotor Vehicle Seatxe2x80x9d. Dudash employs a process in which the guide tube is inserted in an opening in the seat frame. The tube then is swaged on both sides of a flat section of the seat frame to secure the guide tube in the opening. He describes this process as preferably preforming the guide tube with one swaged portion, inserting the tube into the opening, and then forming a second swaged portion in the tube after insertion.
U.S. Pat. No. 3,327,385 issued Jun. 27, 1967 to Raymond H. Shaver for xe2x80x9cMethod of Making Laddersxe2x80x9d shows an arrangement in which the tube is inserted in a hole in a wall structure having a notched opening. The tube is then expanded outwardly into the notch to form a detent or radial key in the notch to anchor the rung against rotation.
One of the reasons that the prior art preforms the first ring is to provide means for locating the tube in the seat frame. This invention eliminates that step so that the entire process is formed in one continuous motion.
The preferred embodiment of the invention employs a process in which a guide tube is inserted into an opening in the seat frame. The frame either may have a flat wall such as an I-beam or C-Frame type structure, or comprise a tubular frame member that has been collapsed to form a pair of adjacent flat walls. An opening is formed in each flat wall. The opening has one or more key slots or notches. The guide tube is then inserted in the opening and a pair of rings is formed in the guide tube, simultaneously, one on each side of the frame walls. The rings are then crushed so that the guide tube material bulges into the notches, thereby providing an attachment that prevents either axial or rotational motion of the guide tube in the frame. Both rings are formed and crushed in one continuous motion of the dies.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description: